Chemistry of common things
Cooking
Doughs
See Doughs, batters, leaveners
Greenery
Trees, O2, CO2
Water
On hydration
Mild dehydration
Drinking slowly?
Erring on the overhydrated or underhydrated side?
3 liters a day, or less?
Coffee's effect on hydration
Alcohol's effect on hydration
On water poisoning
When you drink a large amount in a short time, you dilute (primarily) the balance of salt, and other electrolytes faster than your body knows how to deal with.
At some point, this starts affecting cellular function in general, which is the main thing we mean when we say water poisoning.
Most of your body contains something like 0.15% salt, and you don't want it to be a lot lower, or higher.
...except in your blood, which is roughly 0.9% salt. It's higher mainly because it's a big part of regulating the salt levels in your body.
So diluting your blood leads to lessening or losing that ability to regulate.
You will probably notice being low in salt as
headache,
poorer muscle control,
and possibly vomiting and diarrhea (possibly your body trying to correct things?(verify)).
The fact that you will feel bad, and have probably associated "I feel bloated, I probably need to stop drinking water" is why most people are at negligible risk of this ever happening. (though if you instead confuse it with "I'm dehydrated, I need to drink water", that's not great)
Time is a significant factor, in part in part because your kidneys are happy to make you pee a lot more
- so drinking many liters more than you need over a day is much less of an issue than drinking the same amount within an hour
- peeing that much wastes some salt in the process, but not very much(verify)
Also, it takes a while for you to absorb all water you drink (basically while it's in your gut) - if there's a lot, there isn't even enough time to absorb it.
That time factor is why you see statements like "stay under 3-4 liters of water within in a few hours".
Doesn't distilled water do this a lot quicker?
No.
Sure, tap water and bottled water has things beyond H2O, including sodium.
But when your blood carries something like 0.9% salt (because it's the means of interchange; the rest of your body contains something like 0.15% salt), the difference between 0.003% in tap water and and 0.000% (in theory) in distilled water are both two orders of magnitude lower.
So the difference to the levels that your blood needs is "almost entirely no salt" and "entirely no salt".
In fancier talk, the osmolality of both is so low that they are almost equally hypotonic, so they both have roughly the same osmotic effect on your body.
Which is why quickly drinking liters of almost any water based drink will do this, basically because most water based drinks are almost entirely water.
On bottled water
On filtering water
Activated carbon
Demineralized and distilled water
Distilled water is (nearly-)pure H2O, because distillation means you move the water and leave behind most other things.
Demineralized water means few to no minerals
- ...(unlike fresh natural water, which tends to have minerals in it e.g. due to limestone. Tapwater has more controlled bunch of these things; see also hard water)
- ...but says little about what else may still be in there
- it's useful to keep minerals out of clothes irons (which you want largely to avoid limescale), car batteries (which you want to avoid self-discharge and corrosion), and such.
On contents of demineralized water
Demineralized water often mentions it is not fit for consumption
- in practice it's usually pretty clean water, but it's not guaranteed to be pure
- largely because depending on the process of demineralization, there may be other things still left in there, say, a few bacteria. Your iron or car battery won't care, but you might
- and because it doesn't matter for the intended uses
- (also in part because it's also sold in supermarkets, so it's useful, possibly required, to point this out explicitly)
Does distilled or demineralized water lead to nutritional deficiency?
Water hardness
Hard water refers to water having relatively high mineral content.
Since we're usually talking about fresh water we want to use as drinking water, this focuses mainly on calcium (also magnesium) as this is a common component that comes naturally from the water passing through limestone, chalk, gypsum, or such.
Which gives you things like calcium and magnesium carbonates, bicarbonates, and sulfates.
High is relative - for calcium we're talking talking parts per million, where
- soft water is on the order of 30ppm,
- hard water on the order of 150ppm.
- you get something like 700ppm in a few places
Many other things can qualify for 'mineral content', but typically the amounts are very small,
and/or their appearance is local. (e.g. iron, aluminium, manganese)
Salt is one, in that seawater is technically very hard (6000+ ppm) due to its salt, but since it doesn't evaporate, this doesn't apply to fresh water.
Would you prefer soft or hard water?
It's a few different practical considerations, and none of them are hugely important - and the mentioned effects are frequently overstated.
Arguments for softer:
- aesthetic:
- softer water deposits less scale in showers, drinking glasses, and such
- cost
- softer water deposits less limescale in washing machines, kettles, which can make them last longer (thick scale makes heating less efficient and in extreme cases causes overheating)
- soaps lather more, and you need less detergent (or separate water softener) - can be overstated since many contain softeners anyway
- harder water is less ideal for some industrial processes (and needs fewer additives)
- with soft water, washing clothes wears the fibers a little less
Arguments for harder:
- softer water will pull out metal out of pipes over time, corroding unlined metal pipes more quickly
- (more of a net end effect - there are a handful of other factors on corrosion speed)
- which means water infrastructure can be cheaper to run, particularly that infrastructure is currently older, cheaper pipes.
- Harder water could be considered a dietary supplement
- though this is frequently overstated. The difference from this switch stays is from 'tiny' to 'small' on your calcium needs, and you need to get your minerals elsewhere anyway.
Arguments for either
- "this water tastes nicer" - you probably prefer what you're used to
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See also:
Water containers getting slippery after a while
Carbonated water
Carbonated water means water with CO2 dissolved in it.
Sparkling water - CO2
Soda water - CO2 and bicarbonate of soda, which holds the bubbles better when if you add alcohol.
Mineral water will naturally do this a little.
'Club soda' is a brand of co2-and-bicarbonate, seen mostly in america, though the club it refers to is one in Dublin (Ireland) that commissioned carboa
The dissolved gas acts as a surfactant, which is why it is a mild stain remover.
Fluoride in drinking water
Salty water
Greywater
Electrical resistance of water
See Electronics_notes/Resistors#Resistance_of_fluids